In general, there is known a hybrid construction machine provided with a motor-generator that is jointed mechanically to an engine and a hydraulic pump, and an electricity storage device such as an lithium ion battery or a capacitor (for example, refer to Patent Document 1). In this hybrid construction machine, the motor-generator plays a role of charging power generated by a driving force of the engine in the electricity storage device or assisting in the engine by a powering operation using power of the electricity storage device. Many hybrid construction machines are provided with an electric motor separated from the motor-generator, and the electric motor acts for or assists in a movement of a hydraulic actuator. For example, at the time of performing a revolving movement by the electric motor, the electric motor performs or assists in the revolving movement of an upper revolving structure by power supply to the electric motor, and braking energy at a revolving stop is regenerated to perform a charge of the electricity storage device.
Here, Patent Document 1 discloses a hybrid construction machine provided with a plurality of electric actuators such as a motor-generator, a revolving electric motor, a traveling generator, a lifting magnet and the like, the hybrid construction machine being configured so that in a case where the plurality of electric actuators simultaneously require large power and a total value thereof goes beyond a power supply limit of an electricity storage device, the power is distributed according to preliminarily determined priority of each of the electric actuators.